tail -f myvideofile.mpg | avconv -i - -c:v mpeg2video -b:v '9000k' -c:a copy -mpegts_pmt_start_pid '0x1b8a' -f mpegts pipe:- > /tmp/testmpg

then

tail -f /tmp/testmpg #outputs nothing



tail -f myvideofile.mpg | avconv -i - -c:v mpeg2video -b:v '9000k' -c:a copy -mpegts_pmt_start_pid '0x1b8a' -y -f mpegts /tmp/testmpg

then

ls -lh /tmp/testmpg #size goes up, data is going into it